Effects of thermal treatment and temperature on domain wall dynamics in magnetic microwire

Abstract

Investigation of the influence of thermal treatment and temperature on domain wall (DW) dynamics in bi-stable magnetic microwire with strong unidirectional effect on DW propagation is presented. Measurements of remanent magnetic flux allowed to use in our consideration the force acting on the DW during propagation instead of applied driving field. Then the DW damping coefficient was determined for two values of force acting on the propagating DW for the same sample, but under different conditions (effects of annealing and temperature). Experimental and model temperature dependences of normalized damping coefficient were compared. The theoretical model used takes into account possible changes in DW length caused by mechanical stress and applied force. Experimental and model dependences are in qualitative agreement and show that changes in mechanical stress with temperature are the dominant mechanism responsible for changes in damping coefficient with temperature. Additional analysis shows that the ratio between spin relaxation and eddy current damping is not a constant parameter, but probably increases with increasing DW velocity (applied field).